Axis Powers Begin Invasion of the Kingdom of Yugoslavia with the Bombing of Belgrade

At the end of March 1941 the Kingdom of Yugoslavia was forced to join the Axis, which ignited a popular revolution in the country; this led to a coup d'état and a switch in foreign policy with a re-orientation to join the Allies.

This happened in a crucial moment, when the Wehrmacht was in the final stages of preparation for Operation Barbarossa against the Soviet Union. The successful opening of a campaign in the east required either a diplomatically secured or militarily subdued Balkans - free from the possibility of British intervention - and it was this act of Yugoslavian and primarily Serbian defiance which resulted in Hitler's order for immediate punitive action.

Operation Punishment was the code name for the German bombing of Belgrade during the invasion of Yugoslavia. The Luftwaffe bombed the city on April 6 (Palm Sunday) without a declaration of war, continuing bombing until April 10. More than 500 bombing sorties were flown against Belgrade in three waves coming from Romania where German forces were assembled for the attack on the Soviet Union. Most of the government officials fled, and the Yugoslav army began to collapse.

The attack on Yugoslavia was one of the earliest terror bombings of World War II. In the following days Bulgaria, Hungary, and Italy joined Nazi Germany in partitioning Kingdom of Yugoslavia, with the support of the newly established Nazi-puppet Independent State of Croatia. The country was absorbed within 12 days, and Greece fell a week later, which made the Third Reich the master of most of continental Europe and ready for launching the attack against Soviet Union.

Although Hitler`s orders were specific about the destruction of the city, they were replaced in the last moment for military, communications and logistical targets in the city by Generaloberst Alexander Löhr - the commander of the Luftwaffe formations that bombed Belgrade - and his staff. In the survey prepared by the Luftwaffe ten days after the attack to assess the results obtained by the 218.5 tons dropped, the following targets are mentioned: the royal palace, the ministry of defence, military colleges, the main post office, the telegraph office, railway stations, powerplants and barracks.

Waves of Luftwaffe bombers and Stuka dive bombers bombed Belgrade, killing an estimated 2,274 civilians during the initial April 6-7 bombardment - though some estimates put the figure as high as 5,000 to 17,000 civilians killed - and thousands of buildings were destroyed. According to William Stevenson, in his biography of Sir William Stephenson: "After four days of what the Germans code-named Operation Punishment, some 24,000 corpses were recovered from the ruins. Untold numbers were never found." The most important cultural institution that was destroyed was the National Library of Serbia, with 300,000 unique items including priceless Medieval manuscripts.

German Field Marshal von Kleist said during his trial after the war: "The air raid on Belgrade in 1941 had a primarily political-terrorist character and had nothing to do with the war. That air bombing was a matter of Hitler's vanity, his personal revenge." The bombing without a declaration of war become one of the prosecution's charges which led to the execution of the commander of the Luftwaffe formations involved, General Löhr.

At the end of March 1941 the Kingdom of Yugoslavia was forced to join the Axis, which ignited a popular revolution in the country; this led to a coup d'etat and a switch in foreign policy with a re-orientation to join the Allies. This happened in a crucial moment, when Hitler was in the final planning stage of Operation Barbarossa against the Soviet Union. To subdue Yugoslavia and Greece the invasion of Soviet Union was delayed.